Lan is a double seventh: the seventh son of a seventh son, and heir to great magical power. Eff, his twin sister is also a birth order position, but not one that she wants to fill: she is the thirteenth child. Although her parents do their best to shelter her from taunts and malice, she grows up with the awareness that she is unlucky, a curse on her family, and that it is only a matter of time before she “goes bad.”
In part to remove Eff from the malicious influence of superstitious family members, the family moves out West. In this alternate universe – where the continents include Ashia, Columbia, Aphrika, and Avrupa – one of the most prominent features of the Columbian frontier is the Great Barrier, put into place by Benjamin Franklin and Thomas Jefferson. The Barrier keeps out the many dangerous animals – both magical and mundane – that would otherwise destroy the settlements. While there are communities on the other side of the Barrier, they live their days huddled under magical protections. As Eff grows older, she becomes more and more intrigued by the animals, and convinced that more work needs to be done to study the habits and habitats of these creatures, to help prevent more disasters. At the same time, she is more and more reluctant to use her magic, convinced that it will destroy her and everyone she loves.
The world-building in this novel by veteran author Patricia Wrede was top-notch. There were competing theories of magic use, which all followed their own internal logic. The setting of an alternate past was well done, with a skillful mixture of the events we would expect to have happened with the changes that make this world different from ours.
Although there was no indication that this book was the first in a series, I do wonder (and certainly hope!) that there will be more books about Eff and her world. There were subtle hints that I might not be hoping in vain, as there were a few plotlines that, while not left dangling, could easily be picked up and expanded upon in another volume.
Updated 4/16 to add that I visited Patricia C. Wrede’s website, and Thirteenth Child is, indeed, the first in a trilogy.